3 * Copyright (C) 1992 Krishna Balasubramanian
5 * Sep 1997 - Call suser() last after "normal" permission checks so we
6 * get BSD style process accounting right.
7 * Occurs in several places in the IPC code.
8 * Chris Evans, <chris@ferret.lmh.ox.ac.uk>
9 * Nov 1999 - ipc helper functions, unified SMP locking
10 * Manfred Spraul <manfred@colorfullife.com>
11 * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
12 * Mingming Cao <cmm@us.ibm.com>
13 * Mar 2006 - support for audit of ipc object properties
14 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
15 * Jun 2006 - namespaces ssupport
17 * Pavel Emelianov <xemul@openvz.org>
21 #include <linux/shm.h>
22 #include <linux/init.h>
23 #include <linux/msg.h>
24 #include <linux/vmalloc.h>
25 #include <linux/slab.h>
26 #include <linux/capability.h>
27 #include <linux/highuid.h>
28 #include <linux/security.h>
29 #include <linux/rcupdate.h>
30 #include <linux/workqueue.h>
31 #include <linux/seq_file.h>
32 #include <linux/proc_fs.h>
33 #include <linux/audit.h>
34 #include <linux/nsproxy.h>
35 #include <linux/rwsem.h>
36 #include <linux/memory.h>
37 #include <linux/ipc_namespace.h>
39 #include <asm/unistd.h>
43 struct ipc_proc_iface
{
47 int (*show
)(struct seq_file
*, void *);
50 struct ipc_namespace init_ipc_ns
= {
52 .refcount
= ATOMIC_INIT(2),
56 atomic_t nr_ipc_ns
= ATOMIC_INIT(1);
59 #ifdef CONFIG_MEMORY_HOTPLUG
61 static void ipc_memory_notifier(struct work_struct
*work
)
63 ipcns_notify(IPCNS_MEMCHANGED
);
66 static DECLARE_WORK(ipc_memory_wq
, ipc_memory_notifier
);
69 static int ipc_memory_callback(struct notifier_block
*self
,
70 unsigned long action
, void *arg
)
73 case MEM_ONLINE
: /* memory successfully brought online */
74 case MEM_OFFLINE
: /* or offline: it's time to recompute msgmni */
76 * This is done by invoking the ipcns notifier chain with the
77 * IPC_MEMCHANGED event.
78 * In order not to keep the lock on the hotplug memory chain
79 * for too long, queue a work item that will, when waken up,
80 * activate the ipcns notification chain.
81 * No need to keep several ipc work items on the queue.
83 if (!work_pending(&ipc_memory_wq
))
84 schedule_work(&ipc_memory_wq
);
86 case MEM_GOING_ONLINE
:
87 case MEM_GOING_OFFLINE
:
88 case MEM_CANCEL_ONLINE
:
89 case MEM_CANCEL_OFFLINE
:
97 #endif /* CONFIG_MEMORY_HOTPLUG */
100 * ipc_init - initialise IPC subsystem
102 * The various system5 IPC resources (semaphores, messages and shared
103 * memory) are initialised
104 * A callback routine is registered into the memory hotplug notifier
105 * chain: since msgmni scales to lowmem this callback routine will be
106 * called upon successful memory add / remove to recompute msmgni.
109 static int __init
ipc_init(void)
114 hotplug_memory_notifier(ipc_memory_callback
, IPC_CALLBACK_PRI
);
115 register_ipcns_notifier(&init_ipc_ns
);
118 __initcall(ipc_init
);
121 * ipc_init_ids - initialise IPC identifiers
122 * @ids: Identifier set
124 * Set up the sequence range to use for the ipc identifier range (limited
125 * below IPCMNI) then initialise the ids idr.
128 void ipc_init_ids(struct ipc_ids
*ids
)
130 init_rwsem(&ids
->rw_mutex
);
135 int seq_limit
= INT_MAX
/SEQ_MULTIPLIER
;
136 if (seq_limit
> USHORT_MAX
)
137 ids
->seq_max
= USHORT_MAX
;
139 ids
->seq_max
= seq_limit
;
142 idr_init(&ids
->ipcs_idr
);
145 #ifdef CONFIG_PROC_FS
146 static const struct file_operations sysvipc_proc_fops
;
148 * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface.
149 * @path: Path in procfs
150 * @header: Banner to be printed at the beginning of the file.
151 * @ids: ipc id table to iterate.
152 * @show: show routine.
154 void __init
ipc_init_proc_interface(const char *path
, const char *header
,
155 int ids
, int (*show
)(struct seq_file
*, void *))
157 struct proc_dir_entry
*pde
;
158 struct ipc_proc_iface
*iface
;
160 iface
= kmalloc(sizeof(*iface
), GFP_KERNEL
);
164 iface
->header
= header
;
168 pde
= create_proc_entry(path
,
169 S_IRUGO
, /* world readable */
170 NULL
/* parent dir */);
173 pde
->proc_fops
= &sysvipc_proc_fops
;
181 * ipc_findkey - find a key in an ipc identifier set
182 * @ids: Identifier set
183 * @key: The key to find
185 * Requires ipc_ids.rw_mutex locked.
186 * Returns the LOCKED pointer to the ipc structure if found or NULL
188 * If key is found ipc points to the owning ipc structure
191 static struct kern_ipc_perm
*ipc_findkey(struct ipc_ids
*ids
, key_t key
)
193 struct kern_ipc_perm
*ipc
;
197 for (total
= 0, next_id
= 0; total
< ids
->in_use
; next_id
++) {
198 ipc
= idr_find(&ids
->ipcs_idr
, next_id
);
203 if (ipc
->key
!= key
) {
208 ipc_lock_by_ptr(ipc
);
216 * ipc_get_maxid - get the last assigned id
217 * @ids: IPC identifier set
219 * Called with ipc_ids.rw_mutex held.
222 int ipc_get_maxid(struct ipc_ids
*ids
)
224 struct kern_ipc_perm
*ipc
;
228 if (ids
->in_use
== 0)
231 if (ids
->in_use
== IPCMNI
)
234 /* Look for the last assigned id */
236 for (id
= 0; id
< IPCMNI
&& total
< ids
->in_use
; id
++) {
237 ipc
= idr_find(&ids
->ipcs_idr
, id
);
247 * ipc_addid - add an IPC identifier
248 * @ids: IPC identifier set
249 * @new: new IPC permission set
250 * @size: limit for the number of used ids
252 * Add an entry 'new' to the IPC ids idr. The permissions object is
253 * initialised and the first free entry is set up and the id assigned
254 * is returned. The 'new' entry is returned in a locked state on success.
255 * On failure the entry is not locked and a negative err-code is returned.
257 * Called with ipc_ids.rw_mutex held as a writer.
260 int ipc_addid(struct ipc_ids
* ids
, struct kern_ipc_perm
* new, int size
)
267 if (ids
->in_use
>= size
)
270 err
= idr_get_new(&ids
->ipcs_idr
, new, &id
);
276 new->cuid
= new->uid
= current
->euid
;
277 new->gid
= new->cgid
= current
->egid
;
279 new->seq
= ids
->seq
++;
280 if(ids
->seq
> ids
->seq_max
)
283 new->id
= ipc_buildid(id
, new->seq
);
284 spin_lock_init(&new->lock
);
287 spin_lock(&new->lock
);
292 * ipcget_new - create a new ipc object
294 * @ids: IPC identifer set
295 * @ops: the actual creation routine to call
296 * @params: its parameters
298 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
299 * when the key is IPC_PRIVATE.
301 static int ipcget_new(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
302 struct ipc_ops
*ops
, struct ipc_params
*params
)
306 err
= idr_pre_get(&ids
->ipcs_idr
, GFP_KERNEL
);
311 down_write(&ids
->rw_mutex
);
312 err
= ops
->getnew(ns
, params
);
313 up_write(&ids
->rw_mutex
);
322 * ipc_check_perms - check security and permissions for an IPC
323 * @ipcp: ipc permission set
324 * @ops: the actual security routine to call
325 * @params: its parameters
327 * This routine is called by sys_msgget(), sys_semget() and sys_shmget()
328 * when the key is not IPC_PRIVATE and that key already exists in the
331 * On success, the IPC id is returned.
333 * It is called with ipc_ids.rw_mutex and ipcp->lock held.
335 static int ipc_check_perms(struct kern_ipc_perm
*ipcp
, struct ipc_ops
*ops
,
336 struct ipc_params
*params
)
340 if (ipcperms(ipcp
, params
->flg
))
343 err
= ops
->associate(ipcp
, params
->flg
);
352 * ipcget_public - get an ipc object or create a new one
354 * @ids: IPC identifer set
355 * @ops: the actual creation routine to call
356 * @params: its parameters
358 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
359 * when the key is not IPC_PRIVATE.
360 * It adds a new entry if the key is not found and does some permission
361 * / security checkings if the key is found.
363 * On success, the ipc id is returned.
365 static int ipcget_public(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
366 struct ipc_ops
*ops
, struct ipc_params
*params
)
368 struct kern_ipc_perm
*ipcp
;
369 int flg
= params
->flg
;
372 err
= idr_pre_get(&ids
->ipcs_idr
, GFP_KERNEL
);
375 * Take the lock as a writer since we are potentially going to add
376 * a new entry + read locks are not "upgradable"
378 down_write(&ids
->rw_mutex
);
379 ipcp
= ipc_findkey(ids
, params
->key
);
382 if (!(flg
& IPC_CREAT
))
387 err
= ops
->getnew(ns
, params
);
389 /* ipc object has been locked by ipc_findkey() */
391 if (flg
& IPC_CREAT
&& flg
& IPC_EXCL
)
395 if (ops
->more_checks
)
396 err
= ops
->more_checks(ipcp
, params
);
399 * ipc_check_perms returns the IPC id on
402 err
= ipc_check_perms(ipcp
, ops
, params
);
406 up_write(&ids
->rw_mutex
);
416 * ipc_rmid - remove an IPC identifier
417 * @ids: IPC identifier set
418 * @ipcp: ipc perm structure containing the identifier to remove
420 * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held
421 * before this function is called, and remain locked on the exit.
424 void ipc_rmid(struct ipc_ids
*ids
, struct kern_ipc_perm
*ipcp
)
426 int lid
= ipcid_to_idx(ipcp
->id
);
428 idr_remove(&ids
->ipcs_idr
, lid
);
438 * ipc_alloc - allocate ipc space
439 * @size: size desired
441 * Allocate memory from the appropriate pools and return a pointer to it.
442 * NULL is returned if the allocation fails
445 void* ipc_alloc(int size
)
451 out
= kmalloc(size
, GFP_KERNEL
);
456 * ipc_free - free ipc space
457 * @ptr: pointer returned by ipc_alloc
458 * @size: size of block
460 * Free a block created with ipc_alloc(). The caller must know the size
461 * used in the allocation call.
464 void ipc_free(void* ptr
, int size
)
474 * There are three headers that are prepended to the actual allocation:
475 * - during use: ipc_rcu_hdr.
476 * - during the rcu grace period: ipc_rcu_grace.
477 * - [only if vmalloc]: ipc_rcu_sched.
478 * Their lifetime doesn't overlap, thus the headers share the same memory.
479 * Unlike a normal union, they are right-aligned, thus some container_of
480 * forward/backward casting is necessary:
493 /* "void *" makes sure alignment of following data is sane. */
499 struct work_struct work
;
500 /* "void *" makes sure alignment of following data is sane. */
504 #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
505 sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
506 #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
507 sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
509 static inline int rcu_use_vmalloc(int size
)
511 /* Too big for a single page? */
512 if (HDRLEN_KMALLOC
+ size
> PAGE_SIZE
)
518 * ipc_rcu_alloc - allocate ipc and rcu space
519 * @size: size desired
521 * Allocate memory for the rcu header structure + the object.
522 * Returns the pointer to the object.
523 * NULL is returned if the allocation fails.
526 void* ipc_rcu_alloc(int size
)
530 * We prepend the allocation with the rcu struct, and
531 * workqueue if necessary (for vmalloc).
533 if (rcu_use_vmalloc(size
)) {
534 out
= vmalloc(HDRLEN_VMALLOC
+ size
);
536 out
+= HDRLEN_VMALLOC
;
537 container_of(out
, struct ipc_rcu_hdr
, data
)->is_vmalloc
= 1;
538 container_of(out
, struct ipc_rcu_hdr
, data
)->refcount
= 1;
541 out
= kmalloc(HDRLEN_KMALLOC
+ size
, GFP_KERNEL
);
543 out
+= HDRLEN_KMALLOC
;
544 container_of(out
, struct ipc_rcu_hdr
, data
)->is_vmalloc
= 0;
545 container_of(out
, struct ipc_rcu_hdr
, data
)->refcount
= 1;
552 void ipc_rcu_getref(void *ptr
)
554 container_of(ptr
, struct ipc_rcu_hdr
, data
)->refcount
++;
557 static void ipc_do_vfree(struct work_struct
*work
)
559 vfree(container_of(work
, struct ipc_rcu_sched
, work
));
563 * ipc_schedule_free - free ipc + rcu space
564 * @head: RCU callback structure for queued work
566 * Since RCU callback function is called in bh,
567 * we need to defer the vfree to schedule_work().
569 static void ipc_schedule_free(struct rcu_head
*head
)
571 struct ipc_rcu_grace
*grace
;
572 struct ipc_rcu_sched
*sched
;
574 grace
= container_of(head
, struct ipc_rcu_grace
, rcu
);
575 sched
= container_of(&(grace
->data
[0]), struct ipc_rcu_sched
,
578 INIT_WORK(&sched
->work
, ipc_do_vfree
);
579 schedule_work(&sched
->work
);
583 * ipc_immediate_free - free ipc + rcu space
584 * @head: RCU callback structure that contains pointer to be freed
586 * Free from the RCU callback context.
588 static void ipc_immediate_free(struct rcu_head
*head
)
590 struct ipc_rcu_grace
*free
=
591 container_of(head
, struct ipc_rcu_grace
, rcu
);
595 void ipc_rcu_putref(void *ptr
)
597 if (--container_of(ptr
, struct ipc_rcu_hdr
, data
)->refcount
> 0)
600 if (container_of(ptr
, struct ipc_rcu_hdr
, data
)->is_vmalloc
) {
601 call_rcu(&container_of(ptr
, struct ipc_rcu_grace
, data
)->rcu
,
604 call_rcu(&container_of(ptr
, struct ipc_rcu_grace
, data
)->rcu
,
610 * ipcperms - check IPC permissions
611 * @ipcp: IPC permission set
612 * @flag: desired permission set.
614 * Check user, group, other permissions for access
615 * to ipc resources. return 0 if allowed
618 int ipcperms (struct kern_ipc_perm
*ipcp
, short flag
)
619 { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
620 int requested_mode
, granted_mode
, err
;
622 if (unlikely((err
= audit_ipc_obj(ipcp
))))
624 requested_mode
= (flag
>> 6) | (flag
>> 3) | flag
;
625 granted_mode
= ipcp
->mode
;
626 if (current
->euid
== ipcp
->cuid
|| current
->euid
== ipcp
->uid
)
628 else if (in_group_p(ipcp
->cgid
) || in_group_p(ipcp
->gid
))
630 /* is there some bit set in requested_mode but not in granted_mode? */
631 if ((requested_mode
& ~granted_mode
& 0007) &&
632 !capable(CAP_IPC_OWNER
))
635 return security_ipc_permission(ipcp
, flag
);
639 * Functions to convert between the kern_ipc_perm structure and the
640 * old/new ipc_perm structures
644 * kernel_to_ipc64_perm - convert kernel ipc permissions to user
645 * @in: kernel permissions
646 * @out: new style IPC permissions
648 * Turn the kernel object @in into a set of permissions descriptions
649 * for returning to userspace (@out).
653 void kernel_to_ipc64_perm (struct kern_ipc_perm
*in
, struct ipc64_perm
*out
)
658 out
->cuid
= in
->cuid
;
659 out
->cgid
= in
->cgid
;
660 out
->mode
= in
->mode
;
665 * ipc64_perm_to_ipc_perm - convert new ipc permissions to old
666 * @in: new style IPC permissions
667 * @out: old style IPC permissions
669 * Turn the new style permissions object @in into a compatibility
670 * object and store it into the @out pointer.
673 void ipc64_perm_to_ipc_perm (struct ipc64_perm
*in
, struct ipc_perm
*out
)
676 SET_UID(out
->uid
, in
->uid
);
677 SET_GID(out
->gid
, in
->gid
);
678 SET_UID(out
->cuid
, in
->cuid
);
679 SET_GID(out
->cgid
, in
->cgid
);
680 out
->mode
= in
->mode
;
685 * ipc_lock - Lock an ipc structure without rw_mutex held
686 * @ids: IPC identifier set
687 * @id: ipc id to look for
689 * Look for an id in the ipc ids idr and lock the associated ipc object.
691 * The ipc object is locked on exit.
693 * This is the routine that should be called when the rw_mutex is not already
694 * held, i.e. idr tree not protected: it protects the idr tree in read mode
695 * during the idr_find().
698 struct kern_ipc_perm
*ipc_lock(struct ipc_ids
*ids
, int id
)
700 struct kern_ipc_perm
*out
;
701 int lid
= ipcid_to_idx(id
);
703 down_read(&ids
->rw_mutex
);
706 out
= idr_find(&ids
->ipcs_idr
, lid
);
709 up_read(&ids
->rw_mutex
);
710 return ERR_PTR(-EINVAL
);
713 up_read(&ids
->rw_mutex
);
715 spin_lock(&out
->lock
);
717 /* ipc_rmid() may have already freed the ID while ipc_lock
718 * was spinning: here verify that the structure is still valid
721 spin_unlock(&out
->lock
);
723 return ERR_PTR(-EINVAL
);
730 * ipc_lock_down - Lock an ipc structure with rw_sem held
731 * @ids: IPC identifier set
732 * @id: ipc id to look for
734 * Look for an id in the ipc ids idr and lock the associated ipc object.
736 * The ipc object is locked on exit.
738 * This is the routine that should be called when the rw_mutex is already
739 * held, i.e. idr tree protected.
742 struct kern_ipc_perm
*ipc_lock_down(struct ipc_ids
*ids
, int id
)
744 struct kern_ipc_perm
*out
;
745 int lid
= ipcid_to_idx(id
);
748 out
= idr_find(&ids
->ipcs_idr
, lid
);
751 return ERR_PTR(-EINVAL
);
754 spin_lock(&out
->lock
);
757 * No need to verify that the structure is still valid since the
763 struct kern_ipc_perm
*ipc_lock_check_down(struct ipc_ids
*ids
, int id
)
765 struct kern_ipc_perm
*out
;
767 out
= ipc_lock_down(ids
, id
);
771 if (ipc_checkid(out
, id
)) {
773 return ERR_PTR(-EIDRM
);
779 struct kern_ipc_perm
*ipc_lock_check(struct ipc_ids
*ids
, int id
)
781 struct kern_ipc_perm
*out
;
783 out
= ipc_lock(ids
, id
);
787 if (ipc_checkid(out
, id
)) {
789 return ERR_PTR(-EIDRM
);
796 * ipcget - Common sys_*get() code
798 * @ids : IPC identifier set
799 * @ops : operations to be called on ipc object creation, permission checks
801 * @params : the parameters needed by the previous operations.
803 * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
805 int ipcget(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
806 struct ipc_ops
*ops
, struct ipc_params
*params
)
808 if (params
->key
== IPC_PRIVATE
)
809 return ipcget_new(ns
, ids
, ops
, params
);
811 return ipcget_public(ns
, ids
, ops
, params
);
815 * ipc_update_perm - update the permissions of an IPC.
816 * @in: the permission given as input.
817 * @out: the permission of the ipc to set.
819 void ipc_update_perm(struct ipc64_perm
*in
, struct kern_ipc_perm
*out
)
823 out
->mode
= (out
->mode
& ~S_IRWXUGO
)
824 | (in
->mode
& S_IRWXUGO
);
828 * ipcctl_pre_down - retrieve an ipc and check permissions for some IPC_XXX cmd
829 * @ids: the table of ids where to look for the ipc
830 * @id: the id of the ipc to retrieve
831 * @cmd: the cmd to check
832 * @perm: the permission to set
833 * @extra_perm: one extra permission parameter used by msq
835 * This function does some common audit and permissions check for some IPC_XXX
836 * cmd and is called from semctl_down, shmctl_down and msgctl_down.
837 * It must be called without any lock held and
838 * - retrieves the ipc with the given id in the given table.
839 * - performs some audit and permission check, depending on the given cmd
840 * - returns the ipc with both ipc and rw_mutex locks held in case of success
841 * or an err-code without any lock held otherwise.
843 struct kern_ipc_perm
*ipcctl_pre_down(struct ipc_ids
*ids
, int id
, int cmd
,
844 struct ipc64_perm
*perm
, int extra_perm
)
846 struct kern_ipc_perm
*ipcp
;
849 down_write(&ids
->rw_mutex
);
850 ipcp
= ipc_lock_check_down(ids
, id
);
856 err
= audit_ipc_obj(ipcp
);
860 if (cmd
== IPC_SET
) {
861 err
= audit_ipc_set_perm(extra_perm
, perm
->uid
,
862 perm
->gid
, perm
->mode
);
866 if (current
->euid
== ipcp
->cuid
||
867 current
->euid
== ipcp
->uid
|| capable(CAP_SYS_ADMIN
))
874 up_write(&ids
->rw_mutex
);
878 #ifdef __ARCH_WANT_IPC_PARSE_VERSION
882 * ipc_parse_version - IPC call version
883 * @cmd: pointer to command
885 * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
886 * The @cmd value is turned from an encoding command and version into
887 * just the command code.
890 int ipc_parse_version (int *cmd
)
900 #endif /* __ARCH_WANT_IPC_PARSE_VERSION */
902 #ifdef CONFIG_PROC_FS
903 struct ipc_proc_iter
{
904 struct ipc_namespace
*ns
;
905 struct ipc_proc_iface
*iface
;
909 * This routine locks the ipc structure found at least at position pos.
911 static struct kern_ipc_perm
*sysvipc_find_ipc(struct ipc_ids
*ids
, loff_t pos
,
914 struct kern_ipc_perm
*ipc
;
918 for (id
= 0; id
< pos
&& total
< ids
->in_use
; id
++) {
919 ipc
= idr_find(&ids
->ipcs_idr
, id
);
924 if (total
>= ids
->in_use
)
927 for ( ; pos
< IPCMNI
; pos
++) {
928 ipc
= idr_find(&ids
->ipcs_idr
, pos
);
931 ipc_lock_by_ptr(ipc
);
936 /* Out of range - return NULL to terminate iteration */
940 static void *sysvipc_proc_next(struct seq_file
*s
, void *it
, loff_t
*pos
)
942 struct ipc_proc_iter
*iter
= s
->private;
943 struct ipc_proc_iface
*iface
= iter
->iface
;
944 struct kern_ipc_perm
*ipc
= it
;
946 /* If we had an ipc id locked before, unlock it */
947 if (ipc
&& ipc
!= SEQ_START_TOKEN
)
950 return sysvipc_find_ipc(&iter
->ns
->ids
[iface
->ids
], *pos
, pos
);
954 * File positions: pos 0 -> header, pos n -> ipc id = n - 1.
955 * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
957 static void *sysvipc_proc_start(struct seq_file
*s
, loff_t
*pos
)
959 struct ipc_proc_iter
*iter
= s
->private;
960 struct ipc_proc_iface
*iface
= iter
->iface
;
963 ids
= &iter
->ns
->ids
[iface
->ids
];
966 * Take the lock - this will be released by the corresponding
969 down_read(&ids
->rw_mutex
);
971 /* pos < 0 is invalid */
975 /* pos == 0 means header */
977 return SEQ_START_TOKEN
;
979 /* Find the (pos-1)th ipc */
980 return sysvipc_find_ipc(ids
, *pos
- 1, pos
);
983 static void sysvipc_proc_stop(struct seq_file
*s
, void *it
)
985 struct kern_ipc_perm
*ipc
= it
;
986 struct ipc_proc_iter
*iter
= s
->private;
987 struct ipc_proc_iface
*iface
= iter
->iface
;
990 /* If we had a locked structure, release it */
991 if (ipc
&& ipc
!= SEQ_START_TOKEN
)
994 ids
= &iter
->ns
->ids
[iface
->ids
];
995 /* Release the lock we took in start() */
996 up_read(&ids
->rw_mutex
);
999 static int sysvipc_proc_show(struct seq_file
*s
, void *it
)
1001 struct ipc_proc_iter
*iter
= s
->private;
1002 struct ipc_proc_iface
*iface
= iter
->iface
;
1004 if (it
== SEQ_START_TOKEN
)
1005 return seq_puts(s
, iface
->header
);
1007 return iface
->show(s
, it
);
1010 static struct seq_operations sysvipc_proc_seqops
= {
1011 .start
= sysvipc_proc_start
,
1012 .stop
= sysvipc_proc_stop
,
1013 .next
= sysvipc_proc_next
,
1014 .show
= sysvipc_proc_show
,
1017 static int sysvipc_proc_open(struct inode
*inode
, struct file
*file
)
1020 struct seq_file
*seq
;
1021 struct ipc_proc_iter
*iter
;
1024 iter
= kmalloc(sizeof(*iter
), GFP_KERNEL
);
1028 ret
= seq_open(file
, &sysvipc_proc_seqops
);
1032 seq
= file
->private_data
;
1033 seq
->private = iter
;
1035 iter
->iface
= PDE(inode
)->data
;
1036 iter
->ns
= get_ipc_ns(current
->nsproxy
->ipc_ns
);
1044 static int sysvipc_proc_release(struct inode
*inode
, struct file
*file
)
1046 struct seq_file
*seq
= file
->private_data
;
1047 struct ipc_proc_iter
*iter
= seq
->private;
1048 put_ipc_ns(iter
->ns
);
1049 return seq_release_private(inode
, file
);
1052 static const struct file_operations sysvipc_proc_fops
= {
1053 .open
= sysvipc_proc_open
,
1055 .llseek
= seq_lseek
,
1056 .release
= sysvipc_proc_release
,
1058 #endif /* CONFIG_PROC_FS */